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RYTM in the 13F filings

Rhythm Pharmaceuticals Inc · CUSIP 76243J105

Sector · Pharmaceuticals and biotechnologyTheme · Healthcare: biopharma and medtech· L3VLUP-definedTheme · Pharmaceutical preparations
Quarter
Q3 2026 · early filersQ2 2026Q1 2026Q4 2025Q3 2025Q2 2025Q1 2025Q4 2024Q3 2024Q2 2024Q1 2024Q4 2023
Quarter end
31 Mar 2026
the date the book describes
Filed
27 Oct 2026
latest of these filings; the earliest 12 May 2026
Managers listing it
30
at least, of 95 tracked, among listed positions
Comparable managers
91
filed both Q4 2025 and Q1 2026; 10 listed it in both
Shares listed
11,798,310
combined, among listed positions
Reported value
$1.0bn
combined, at the quarter end

AllianceBernstein LP. Values in this filing are at the previous quarter end's prices; its share count is the quarter end's.

Among the 91 comparable managers: 18 buyers (opened or added shares) and 14 sellers (trimmed or exited), at least, among listed positions. Their net change in shares was +2,268,228.

Managers listing RYTM in Q1 2026

Share of 13F value is the position’s reported value over everything the manager reported that quarter. The share change is against Q4 2025, and only where both filings list the position. A rise in value with no rise in shares is the price, not buying.

30 of 30 holders

ActionFiling
Fidelity (FMR LLC)1,689,671$147munder 0.1%Trimmed-16,64615 May 2026 (the filing on sec.gov)
T. Rowe Price Associates Inc1,654,876$144munder 0.1%Added+94,02915 May 2026 (the filing on sec.gov)
Citadel Advisors LLC1,418,619$123munder 0.1%Added+1,265,29715 May 2026 (the filing on sec.gov)
AllianceBernstein LP910,413$97munder 0.1%Trimmed-19,82015 May 2026 (the filing on sec.gov)
Capital Research Global Investors1,115,460$97munder 0.1%Added+130,37413 May 2026 (the filing on sec.gov)
Janus Henderson Group Ltd918,153$80munder 0.1%Trimmed-207,97218 May 2026 (the filing on sec.gov)
Point72 Asset Management LP846,801$74m0.09%Added+417,38115 May 2026 (the filing on sec.gov)
Woodline Partners LP758,891$66m0.25%Added+70,11215 May 2026 (the filing on sec.gov)
Millennium Management LLC451,825$39munder 0.1%Added+265,11615 May 2026 (the filing on sec.gov)
Artisan Partners LP390,669$34m0.05%Added+127,07813 May 2026 (the filing on sec.gov)
Invesco Ltd364,306$32munder 0.1%Added+73,15612 May 2026 (the filing on sec.gov)
Wellington Management Group LLP273,757$24munder 0.1%Added+23,60115 May 2026 (the filing on sec.gov)
Squarepoint Ops LLC262,968$23munder 0.1%Added+230,13915 May 2026 (the filing on sec.gov)
Renaissance Technologies LLC258,011$22munder 0.1%Trimmed-83,18214 May 2026 (the filing on sec.gov)
Capital World Investors115,693$10munder 0.1%Held013 May 2026 (the filing on sec.gov)
Neuberger Berman Group LLC73,434$6.4munder 0.1%Trimmed-13827 Oct 2026 (the filing on sec.gov)
AQR Capital Management LLC59,279$5.2munder 0.1%Trimmed-10,76715 May 2026 (the filing on sec.gov)
Balyasny Asset Management LLC52,967$4.6munder 0.1%Trimmed-19,31515 May 2026 (the filing on sec.gov)
Susquehanna International Group LLP50,784$4.4munder 0.1%Added+46,68715 May 2026 (the filing on sec.gov)
D. E. Shaw & Co.32,652$2.8munder 0.1%Added+1,29615 May 2026 (the filing on sec.gov)
PDT Partners LLC27,232$2.4m0.14%Trimmed-32,20415 May 2026 (the filing on sec.gov)
Tudor Investment Corp19,646$1.7munder 0.1%Newnew15 May 2026 (the filing on sec.gov)
ExodusPoint Capital Management LP17,775$1.5munder 0.1%Trimmed-57,36614 May 2026 (the filing on sec.gov)
Marshall Wace LLP9,628$837kunder 0.1%Newnew15 May 2026 (the filing on sec.gov)
Hudson Bay Capital Management LP9,120$793kunder 0.1%Newnew13 May 2026 (the filing on sec.gov)
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Largest increases and reductions, by shares

Q4 2025 to Q1 2026, among managers that listed it in both quarters or opened it.

Increases

Reductions

New positions and exits

At least these many: a manager is shown exiting only where its own filing shows the position gone.

New (6)

Exited (3)

Ownership over time

Every quarter on file. A quarter-end value moves with the price as well as with the shares held; buyers and sellers count comparable managers, by shares.
6 in Q3 2024 to 9 in Q2 2026

Tracked managers listing it, at least.

03581020182019202020212022202420252026
the quarter shown share split complete books; unmarked quarters rest on listed positionsClick a quarter to open it.
RYTM by quarter
QuarterHoldersReported valueBuyersSellers
Q1 20181$750kn.a.n.a.
Q2 20183$76mn.a.n.a.
Q3 20183$91mn.a.n.a.
Q4 20181$88mn.a.n.a.
Q1 20192$90mn.a.n.a.
Q2 20191$72mn.a.n.a.
Q3 20191$74mn.a.n.a.
Q4 20191$99mn.a.n.a.
Q1 20201$66mn.a.n.a.
Q2 20201$98mn.a.n.a.
Q3 20201$95mn.a.n.a.
Q4 20201$134mn.a.n.a.
Q1 20211$87mn.a.n.a.
Q2 20211$77mn.a.n.a.
Q4 20211$593kn.a.n.a.
Q1 20221$474kn.a.n.a.
Q2 20221$628kn.a.n.a.
Q3 20222$43mn.a.n.a.
Q4 20221$36mn.a.n.a.
Q3 20233$33mn.a.n.a.
Q4 20234$61m31
Q1 20243$40m20
Q2 20244$32m13
Q3 20246$80m43
Q4 20244$131m41
Q1 20254$147m31
Q2 20255$160m23
Q3 20259$496m72
Q4 202510$537m1616
Q1 20267$450m1814
Q2 20269$859m1418

Compare with…

Holders over time, buyers and sellers, and the managers holding both, side by side for up to four stocks.

RYTM and LLY →RYTM and JNJ →RYTM and VRTX →Choose a stock to compare with RYTM →

How much of the picture this is

A 13F is a manager’s long US-listed equity book at a quarter end, filed up to 45 days later. It shows no shorts, cash, bonds or performance, and it is never today’s portfolio. Large books are listed to their largest positions, so a manager missing from this table may still hold a small position below that line. These are 95 tracked managers, not the institutional market.

Which funds own RYTM, latest filings →Back to the 13F Explorer →